Antenatal Care and Screening Flashcards
Characteristics of morning sickness if pregnancy
- Reasons unclear
- Affects 80-85% women
- Worse in conditions where HCG is higher e.g. twins, molar pregnancy
- Can progress to hyperemesis gravidarium
- Usually much better by week 16
What are the normal physiological cardiac out-put changes in pregnancy
- CO increases by 30-50%
- CO=SV x HR, HR increases from 70-90bpm
- Palpitations common
- At term, blood flow to uterus must exceed 1L/min
What are the normal physiological BP changes in pregnancy
- Drops in the second trimester
- Expansion of the uteroplacental circulation
- A fall in systemic vascular resistance
- Reduction in blood viscosity
- Reduction in sensitivity to angiotensin
- BP return to normal in 3rd trimester
What are the normal physiological changes to the urinary system in pregnancy
- Bladder capacity reduced in 3rd trimester because of pressure
- Increased urine output
- Renal plasma flow increases 25-30%
- Glomerular filtration rate increases by 50%
- Serum urea and creatinine decrease - partly due to increased GFR and partly due to dilutional effect on increased plasma
- UTI
- Increase in urinary stasis
- Hydronephrosis physiological in 3rd trimester and makes pyelonephritis common
- Associated with preterm labour so needs treated
Normal physiological respiratory changes in pregnancy
- Progesterone acts centrally - reduced CO2
- Increased tidal volume
- Increased respiratory
- Increased plasma pH
- O2 consumption increased by 20%
- Plasma PO2 unchanged
- Hyperaemia of resp mucous membranes
Normal physiological GI changes in pregnancy
- Oesophageal peristalsis reduced
- Gastric emptying slows
- Cardiac sphincter relaxes
- GI motility reduced due to
- Increased progesterone
- Decreased motilin
Who gets prepregnancy counselling
- Ideally all women
- Vital for women with previous health or pregnancy problems
- In Scotland 1/3rd pregnancies unplanned
Primary care pre-pregnancy counselling
- General health measures
- Improve diet
- Optimise BMI
- Reduce alcohol consumption
- Smoking cessation advice
- Folic acid - 400mcg
What problems does obesity have in pregnancy
- Higher rate of poorer outcomes
- Affects function of uterus
- Routine measurements difficult
- Venous thromboembolic events more common
What problems does alcohol have in pregnancy
- Foetal abnormalities
- Foetal alcohol syndrome
What problems does age have in pregnancy
- Teenagers more socially deprived, smoke more, book late, do not receive proper antenatal care
- Older women (>40) have a higher chance of pre-existing medical conditions, develop more complications (gestational diabetes, hypertension etc.) an have dramatic increase in chances of chromosomal disorders
What problems does parity have in pregnancy
- Pre-eclampsia is predominantly a condition of mull parity, occurring in the first pregnancy
- Gran multiparity (4 or more) predisposes women to post-partum haemorrhage
What problems does occupation have in pregnancy
- May put themselves or foetus at risk
- Busy jobs with inadequate periods of rest, exposure to substances
What problems does substance misuse have in pregnancy
- Mother may not see antenatal care
- Heroin, methadone and benzodiazepine are addictive to the foetus and cause withdrawal syndrome at birth
- Cocaine is associated with abruption resulting foetal death
Hoe does prepregnancy counselling help those with pre-existing medical conditions
- Optimise maternal health
- Psychiatric health important
- Stop/change unsuitable drugs
- Advise regarding complications associated with maternal medical problems
- Occasional advise against pregnancy
Common previous maternal pregnancy problems
- Counsel regarding risk of recurrence
- C-section - after 2 customary to deliver this way
- DVT
- Pre-eclampsia
Actions to reduce recurrence of previous maternal pregnancy problems
- Thromboprophylaxis
- Low dose aspirin
Common previous foetal pregnancy problems
- Counsel regarding risk of recurrence
- Pre-term delivery
- Intrauterine growth restriction
- Foetal abnormality
Action to reduce recurrence of previous foetal pregnancy problems
- Treatment of infections
- High dose of folic acid
- Low dose aspirin
What are the aims of antenatal examination
- Mother
- Problems - pre-existing or developing illness
- ‘Minor’ problems such as anaemia
- Foetus
- Small gestational age
- Foetal abnormality
- Social
- Support
- Domestic violence
- Psychiatric illness
What is done in the antenatal examination
- Routine enquiry - feeling well, foetal movements (20 wks)
- Blood pressure - detect hypertension
- Urinalysis - diabetes, UTI
- Abdominal palpation
- Foetal heartbeat
What is done on abdominal palpation in antenatal examination
- Assess symphyseal fundus
- Height (SFH)
- Estimate size
- Estimate liquor volume
- Asses lie
- Determine presentation
- If breech after 36 weeks offer external cephalic version
What is antenatal screening
- Offered to all women but not compulsory
- Appropriate counselling prior important
- Allows conditions to be detected and treated
What infection screening is done in antenatal screening
- Hep B - can provide passive and active immunisation for baby
- Syphilis - treat with penicillin
- HIV - maternal treatment and careful planning reduces transmission
- MSSU - UTI
- Rubella - up to 16 weeks, mental handicap, blindness deafness and heart defects
Anaemia and isoimmunisation antenatal screening
- Iron deficiency anaemia - common
- bloods at 28/40 weeks
- Iron tablets
- Isoimmunisation
- Rhesus disease - foetal anaemia can occur (can lead to foetal death)
- Anti-c, anti-kell
What can be screened for on first US scan
- Ensure viable
- Multiple pregnancy
- Identify abnormalities incompatible for life
- Down’s syndrome screening
What is looked for on a detailed anomaly US scan
- Systematic structural review of baby
- Not possible to identify all problems
- can identify problems that need intrauterine or postnatal treatment
What is Down’s syndrome
- Chromosomal abnormality
- Characterised by 3 copies of chromosome 21
- Overall risk - 1 in 700
What is considered risk is considered high for Down’s syndrome
- 1 in 150
- Further testing offered
How does risk for Down’s syndrome increase with age
- Increases with age
- 1 in 1667 - 20 years
- 1 in 30 45 years
What are the testing options offered for Down’s syndrome
- Chorionic villus sampling (CVS) - 10-14 weeks, 1-2% risk
- Amniocentesis - 15 weeks, 1% risk
- Non-invasive prenatal testing
- Maternal blood testing, detects foetal cell-free DNA
- Can look for trisomies
- Not offered on NHS
- If high risk, invasive testing still recommended
How is Down’s syndrome screened for in the first trimester
- 10-40 weels
- Maternal risk factors
- Serum B-hCG
- Pregnancy-associated protein A (PAPP-A)
- Foetal nuchal translucency (NT) measurement
- Detection rate = 90%, invasive rate = 5%
How is the nuchal translucency measured
- Taken between crown rump lengths of 45-84mm
- Increases with gestation
- Incidence of abnormalities related to size (not appearance)
Screening for neural tube defect
- Not routinely offered
- Personal/family history - take 5mg folic acid
- First trimester - detect anencephaly, spina bifida
- Second trimester - biochemical screening
- If unable to NT measurement
- Maternal serum tested for alpha fetoprotein - <2 high
What is the purpose of second trimester screening
- Detecting foetal abnormality
- Good screening test for structural abnormalities but poor for chromosomal
